Odd Word Out

These brain teasers rely on your ability to recognize groups of common attributes. For each of these puzzles you'll need to figure out why the words or letters are grouped as they are. Sometimes you will be asked to pick the odd-one-out or to place a new word into the correct group.

aww, heck. I thought I got it, but it wasn't what you had, however, what I found is true of all the words except horseshoe, all the rest have two sets of the same three letters, some in the same order, others in different order. Its interesting, I guess because all the letters were dupes it also had this other property. But my answer WAS a little farfetched, I thought...

Did not get this one at all. Each time I went over the list I picked out a different one to eliminate. Sad how poorly my brain works. But I'm like a dog with a bone, I never give up. Thanks for the brain workout.

Brilliant! Especially since mNy of the words end in S! If you don't get how simple it is by seeing the Pattern right away it could be confusing since thas are nice long intelligent words! Great teaser!

An absolutely *Totally Awesome teaser. Even after seeing what was involved, I enjoyed it even more. The clue would have easily given away the answer. It could be that some of us, are geared toward loooking for certain tricks, that we get the answer, too quickly! I would still enjoy it, anyway! Keep bringing these type of teasers, on out! Fantastic work!

I saw all the repeating letters, but got sidetracked when I saw that there were 3 other solutions.
Caucasian - no pre-/suffix
Horseshoer - only one defining a job
(forgot word)ing - only word to end in ing